The Nesjavellir Geothermal Power Station is the second largest geothermal power plant in Iceland. The facility is located 177 m (581 ft) above sea level in the southwestern part of the country, near Thingvellir and the Hengill Volcano.

Plans for utilizing the Nesjavellir area for geothermal power and water heating began in 1947, when some boreholes were drilled to evaluate the area's potential for power generation. Research continued from 1965 to 1986. In 1987, the construction of the plant began, and the cornerstone was laid in May 1990. The station produces approximately 120MW of electrical power, and delivers around 1,800 litres (480 US gal) of hot water per second, servicing the hot water needs of the Greater Reykjavík Area.